This invention relates to a nozzle arrangement for an ink jet printhead. In particular, this invention relates to a nozzle arrangement that incorporates a spring movement in a working stroke.
The Applicant has invented a printhead chip which is capable of printing text and images at a resolution of up to 1600 dpi. While developing this technology, the Applicant has filed many patent applications covering various inventions which have been conceived during this development.
A large proportion of the inventions are in the field of micro electro-mechanical systems. These systems allow up to 84000 nozzle arrangements to be formed on a single printhead chip. As a result of various constraints arising from the necessity for the high density of nozzle arrangements, it has been necessary to design the systems in such a way that each nozzle arrangement, in most cases, includes one or more moving parts which serve to eject the ink from each of the nozzle chambers defined by the nozzle arrangements.
As a result of the extent of work carried out in this area, the applicant has identified that it would be advantageous to provide a means whereby movement of an actuator in such nozzle arrangements remained consistent and was not dependent upon the application of a possibly variable force to the actuator.
FIG. 1 of the drawings shows a prior art example of an actuator mechanisms 10 which uses piezo-electric movement to achieve the ejection of ink from an ink ejection port 12. Applicant has identified a disadvantage with such an arrangement in that the extent of movement of a piezo-electric element 14 is dependent upon strength of a piezo-electric signal. Accordingly, Applicant has found that it can be difficult to achieve consistent movement of the element 14.
This invention is directed to providing a means whereby consistent actuating movement of a prime mover in a nozzle arrangement can be achieved.
According to the invention, there is provided a nozzle arrangement for an ink jet printhead, the nozzle arrangement comprising
a substrate; and
a micro electro-mechanical actuator mechanism arranged on the substrate and comprising
a prime mover that is displaceable between a released position and a loaded position, with respect to the substrate;
at least one spring device connected between the prime mover and the substrate and configured so that, when the prime mover is displaced into the loaded position, the, or each, spring device is tensioned; and
a loading mechanism that is operatively arranged with respect to the prime mover to act on the prime mover so that the prime mover is displaced into the loaded position, the loading mechanism being connectable to a control system so that the loading mechanism can be de-activated when required to release the prime mover allowing the prime mover to be displaced under action of the, or each, spring device.
The invention is now described, by way of example only, with reference to the accompanying drawings. It is to be understood that the specific nature of the following description is not to be construed as limiting the scope of the above summary.